This invention discloses acid derivatives of ring substituted 3-hydroxy-pyridines.
These compounds are new and show a plant growth regulatory activity, which can be usefully exploited in the agricultural field. The art discloses compounds with similar chemical structure, but which to our knowledge have not been tested or commercially exploited for plant growth regulation.
In Acta Chem. Scand. 23 (1969) p 1791-1796, there is disclosed a way to synthetise such 3-alkoxypyridines by way of alkylation of 3-pyridinols in dimethyl sulfoxide. In the J. Heterocyclic Chem. 5 (1968) p 281-283, we find the ethyl ester of .alpha.-(3-pyridyloxy)-propionic acid and of 3-pyridyloxy acetic acid disclosed as novel intermediate products in the synthesis of furo-[2,3-c]pyrimidine. In these articles there is given no indication about a possible use for these compounds, which are structurally closest to the ones disclosed in this invention.
These ist an article in the J. Org. Chem. 23 (1958) p 1614-1616, wherein the acid and ethyl esters of some 2-pyridyloxy acetic acids substituted by chlorine and bromine in the pyridyl ring were synthetised in order to be compared for their herbicidal activity with herbicides, such as 2,4-dichlorophenoxy acetic acid and 2,4,5-trichlorphenoxy acetic acid.
Further compounds with vaguely similar chemical structure have also become known as biocidal, microbiocidal and fungicidal agents or as agents for combatting animal pests or enteroparasites, see the U.S. Pat. No. 3,249,619 or the German Offenlegungsschrift No. 2 103 728. Similar 2-pyridinol compounds are described as herbicides in the U.S. Pat. Nos. 3,671,486 and 3,755,339.